The present invention relates in general to information/control panels in mobile vehicles such as a car, truck, train, bus, or airplane, and, more specifically, to touchscreen control panels adapted to provide touch-based menu controls separate from a visual menu for use by a passenger in a secondary seating location, especially visually impaired passengers.
A typical transportation vehicle such as a car or truck includes many operator-controlled systems and accessories. In order to handle the diverse interactions with vehicle electronic systems such as a climate control system, media and entertainment system, driver information system, navigation system, or wireless communication system, a centralized control panel interface may be provided on the vehicle dashboard or instrument panel for a driver and front seat passenger or on seatbacks or console surfaces for passengers in other vehicle seating rows. Such centralized units can result in ease of use and lowering overall manufacturing costs. One common type of human-machine interface involves the use of a touchscreen for visibly displaying different context-sensitive menus with various graphical elements associated with the controlled features or systems for manipulation by the user's fingers in order to adjust various parameters of the associated electronically-controlled systems.
The ease of use and the amount of time required for making appropriate selections are important considerations for vehicle design in order to enable efficient use of the controls and to maximize the time available for the driver to attend to other tasks. In order to make displayed information and control actions on the touchscreen accessible to a front seat passenger, the touchscreen control panel is typically located at a “center stack” on the instrument panel or dashboard of the vehicle. In addition, a touchscreen control panel may also be located in other seating rows for information display and passenger control of various vehicle accessories including climate control functions and audio system functions. While the display presents a contextual menu according to the vehicle state and/or previous menu selections, the user can execute gestures (e.g., taps) on the touch-sensitive screen which are interpreted by a controller to initiate corresponding actions.
Automotive touchscreen controls are known which provide haptic feedback by mechanically moving (e.g., vibrating) the surface of the touchscreen in association with activation of a particular command (see, e.g., U.S. Pat. Nos. 7,834,857 and 8,269,726). Haptic vibration requires a motor, solenoid, or piezoelectric device to produce mechanical vibration of the touchscreen, thereby imposing significant limitations upon the touchscreen technologies and materials that can be used. Such systems are also subject to mechanical wear and failures, and they produce undesirable noise when activated.
Another type of haptic feedback for touchscreens is based upon electrostatic friction between a touchscreen surface and a user's finger (without any actual vibration of the touchscreen). For example, a system known as Tesla-Touch has been described (see, e.g., U.S. patent application publication 2012/0327006) employing a transparent electrode disposed over the touchscreen for interacting with a moving finger that slides over the transparent electrode, wherein a periodic electrical signal is applied between the electrode and finger to induce an attractive force by an electric field that is modulated to vary the friction in a desired manner such that when the finger is moved across the screen surface in the presence of the modulation, the friction pattern will simulate the feeling of different textures. For example, a sinusoidal modulation may feel like a wavy surface and a square wave modulation may feel like parallel lines or ridges.
Based on position feedback defining the location where a user's finger is making contact, the electrostatic modulation may be varied so that the sensed texture changes as the finger moves over different screen locations. With a context-sensitive menu being displayed on the touchscreen, various feature icons can appear to be raised by having an increased (perceived) sliding friction in order to allow easier positioning of the finger over the desired icon. The user can obtain additional haptic feedback on “slider” type controls by changing the friction efforts relative to the position on the slider (e.g., changing friction associated with changing audio volume, cabin temperature, or fan speed). Moreover, the haptic feedback can change the user's feel of the friction in order to indicate when a desired on/off feature setting has been selected.
Typical control panel operation is performed independently of the identity of the user who is engaged with operating the controls (i.e., whether it is the driver or a passenger). During active driving, some features of the controller may be made unavailable (e.g., suppressed from the menu selections) to prevent a driver from attempting to access tasks that would result in distraction. With the feature being suppressed, a passenger has also been prevented from accessing the menu selection since it has typically not been possible to determine which vehicle occupant is touching the control screen. However, it is possible to discriminate between the occupants in a touchscreen control system having a modulated signal injected between the user and the transparent electrode to generate the electrostatic friction by introducing unique signal properties for each separate user, as disclosed in U.S. patent application publication 2016/0299617A1, which is incorporated herein by reference in its entirety. When the passenger can be distinguished from the driver, it becomes possible to continue to provide passenger access to the driver-restricted features (e.g., entering navigation routing information or pairing Bluetooth devices) during active driving.
The features available for adjustment and the associated information displayed on a touchscreen control include some that would be useful to a visually impaired passenger. For example, it would be desirable to empower a non-sighted passenger to adjust the heating/cooling settings for their seating position, to change the volume or media source of the audio entertainment system, or to adjust other features for themselves or other occupants of the vehicle. Voice recognition can be used, but it is typically impractical to provide the capability to distinguish between the voice of the driver or other occupants. Therefore, it would be necessary to restrict access to certain features during active driving for all spoken commands. In addition, the activity of others using spoken commands could divert some attention of the driver. Therefore, it would be desirable to adapt a touchscreen control panel for use by a visually impaired passenger while maintaining normal functionality for the driver.